On Friday, EPA finally issued its long-awaited revised risk assessment for tetrachloroethylene, also known as perc or PCE. EPA also issued a fact sheet summarizing its current views about PCE and how the new risk assessment fits into the Clean Air Act, Safe Drinking Water Act, and CERCLA regulatory regimes.

Because PCE is present at so many Superfund Sites, and given the number of dry cleaners – including many in residential areas – still using PCE, EPA seemed to go out of its way to minimize the significance of the new risk assessment. Among the points it made:

Having ones clothes dry cleaned with PCE will not result in increased risk

The new risk assessment will result in no immediate change to MCLs, Superfund cleanup levels, or the NESHAP for PCE.

Why do we even care, then? Because EPA will review its PCE NESHAP in 2014. Because EPA is reviewing its MCL for PCE, and a more stringent MCL will result in a new and more stringent ARAR for Superfund cleanups. Because site-specific risk assessments utilize the IRIS information and will thus now result in more stringent cleanup standards.

I should note that, precisely because this issue has been pending for some time, and the data on which the new risk assessment has been available to states, some states have already tightened risk assessment standards for PCE and have already ratcheted down, for example, permissible indoor air concentration limits. Nonetheless, for EPA to adopt this risk assessment on a nationwide basis remains significant.